Smallest workshop promises big benefits in nanomanufacturing

(Nanowerk News) Murali M. Sundaram has a dream. One day, he hopes to see a low-cost and sustainable manufacturing facility capable of machining all sorts of substances at the smallest scales, without the need for a super-clean laboratory environment.

Murali M. Sundaram"Success in manufacturing is only possible if the common man is involved," said Sundaram, assistant professor of mechanical engineering in UC's College of Engineering and Applied Science. "Sustainability requires low-cost. Investment will follow affordability."

Director of UC's Micro and Nano Manufacturing Laboratory, Sundaram is exploring a variety of cutting-edge processes to be used to machine substances at very small scales. The ability to manufacture at micro-scales and nano-scales has potential application in biomedical, automotive, microelectronics, paintings and coatings, and measurement industries.

"The key is to move from the clean room into the real world." Sundaram said. "To do that we have to not only develop these processes, but to make them reliable and affordable."

Another goal is to apply processes to a variety of materials. Over the past half-century, silicon has been used in many microelectronic devices, so its properties are widely understood. Sundaram notes that some devices call for materials other than silicon.

"When I was student, I often heard, 'We can do micromachining on any substance as long as it is silicon,'" Sundaram said. "But in the real world we need technologies to micromachine a variety of materials. This was my motivation to explore nontraditional and alternative processes."

Although the processes Sundaram is exploring are often called "alternative manufacturing processes," he notes that, for some tasks, the only workable process is an "alternative" process. A major factor, particularly at nano-scales, is that materials don't behave the same as they do at "normal" scales.

"Let's say I want to write a program for a robot to move an object," Sundaram said. "It should be simple. Locate the object, pick it up, move it drop it. However, at the nano-scale, the object will not drop. Gravity is not the major force at that scale."

At nano-levels, properties change. There is much to learn about how materials behave at that scale.

"First, I ask what is the difference?" Sundaram said. "Then, what causes the difference? Then how can I use the difference in manufacturing?"

Sundaram's lab is engaged in an effort to find a nano-equivalent to common machining techniques like drilling or grinding. There is no nano-equivalent to sandpaper, but tiny particles of diamond can be bounced between an ultrasonically vibrated tool and the workpiece, generating holes smaller than 400 nanometers in diameter. Even here, scale makes a difference.

"If I were to drill a hole in a sheet of metal, I would expect that hole to be there next week or next year," Sundaram said. "If I make a hole just a few atoms wide, I will find that atoms gradually move into the open space."

Even at this scale, environmental concerns arise. Nano-abrasives may knock nothing larger than a nano-particle from the target, but enough nano-particles eventually add up to an environmental concern.

Working with doctoral candidate Sagil James, Sundaram is exploring green nanomanufacturing technology to monitor and control the production of toxic nanoparticles. The goal is a cost-effective method to monitor and prevent hazardous nanoparticles from entering the ecosystem and adversely affecting the environment.